In my search for a cheap and good bike I have been looking at different options. They have been from random people with fliers in the student buildings, to Huuto (the Finnish version of Ebay), to others like the repaired bikes at Aurinkotehdas. I have even considered buying from Amazon.co.uk, where I actually asked the Finnish customs officials at Tulli if I would have to pay additional import taxes (the answer to that was no).
However, later I found out that the Police Stations all over Finland organize auctions (huutokauppa) in order to get rid of different items that are either confiscated or lost and never reclaimed. The biggest of those auctions is the bike sales.